Q: 3 monitors from a single 5870

To run three monitors, all adapters to "legacy" display technologies must use ACTIVE POWERED adapters.

Mac Pro (Early 2009), Mac Pro (Mid 2010), Mac Pro (Mid 2012): Issues with three displays and multiple DVI, HDMI connections

Mac Pro (Early 2009), Mac Pro (Mid 2010), Mac Pro (Mid 2012): supported display configurations for the Mac Pro.

http://support.amd.com/us/eyefinity/Pages/eyefinity-dongles.aspx

What resolution? not every monitor needs dual link, and 3 display outputs does seem harder to achieve.

1920 by 1200 requires only Single-Link, but All must be ACTIVE, Powered adapters. If there is a USB pigtail, it must be plugged in for power.

I messed up the link above. This one should point to AMD's list of "Gold" qualified adapters:

AMD Eyefinity Validated Dongles

Apple says:

That will work using Apple's Dual-Link adapters which cost US$100 each.

As will these adapters:

available here for US$32.48 with SuperSaver shipping:

http://www.amazon.com/Accell-B087B-006B-DisplayPort-Single-Link-Certified/dp/B00 4071ZXA/ref=sr_1_2?s=pc&ie=UTF8&qid=1343515421&sr=1-2&keywords=accell+B087B-006B

lesterfromspace-

Amazon's search included the wrong part. The link I originally posted is for  "regular" DisplayPort to DVI.

You need the MiniDisplayPort to DVI. I have fixed the link. So sorry.

What if I want to use 2 DVI and 1 HDMI? Must all adapters used be Dual Link Active (i.e. Apple's $100 adapters)

Thank you,

ACTIVE Adapters are required when using more than TWO Adapters.

But Dual-Link are only required for wider than 1920 wide.

Accell and StarTech ACTIVE adapters can be used at much lower cost if you are not using wide displays.

DVI (1920 x 1200 maximum resolution)

<http://www.accellcables.com/B087B-006B.html>

HDMI

<http://ca.startech.com/AV/Displayport-Converters/Mini-DisplayPort-to-HDMI-Active -Video-and-Audio-Adapter-Converter-Mini-DP-to-HDMI-1920x1200~MDP2HDS>

Thank you, Malcolm.

My issue is that my 5870 card has 2 Mini Display Ports and 1 DVI port.

I bought Apple's Dual Link Active DVI - Mini Display Port adapters and plugged both of my DVI displays in (Dell 23 inch) -  These are both plugged in on the Mini Display Ports on the 5870 card. and they work, but adding my TV using a DVI-HDMI converter cable on the final open DVI port doesn't work.

Any thoughts? I don't have 3 Mini Display Ports. Using a 2010 Mac Pro Tower btw.

Thank you in advance!

I was thinking about it and did you mean that if I used an active HDMI-MDP converter for my TV screen, that it would work then with the 2 other displays?

That would mean that one of the other two dell displays would be DVI-DVI Active-MDP and the second one would just be straight DVI.. correct? As the ATI 5870 only has 2 Mini Display Ports and a DVI port.

Thank you again for all of your help.

Yes, you can connect one DVI display to the the card's DVI port, the other to an active DVI adapter, and use the active HDMI adapter for the TV.

If you don't need audio on the HDMI cable, you could use your two Apple DVI adapters, and use a simple DVI to HDMI adapter or cable for the TV.